Carburetor for internalcombustion engines



CARBURETOR FOR INTERNAL-COMBUSTION ENGINES Filad Sept. 16, 1943 v 5 KZ .13

common FOR INTERNAL- USTION ENGENES i This invention relates to a carburetor for lnternal combustion engines.

In the conventional carburetor the idle jet operates independently of the main jet. When the engine is idling or operating at a very slow speed, the throttle of a conventional carburetor is practically closed and the car is operating entirely on the idle jet because there is not enough air going through the venturi to cause the main jet to flow fuel out of the bowl. At this-timethe main jet is dry and there is no gasoline in the passageway leading to the main jet from the float bowl higher than the gasoline level in the bowl. If the throttle valve is now suddenly opened to. say, quarter open position, the vacuum in the manifold will drop and the idle lot will lean out or cease to feed. Due to the fact that time is. required for the air flowing by the main jet or nonale to pull the gasoline fromv fioat level to nozzle height, there is a delay in gasoline feeding which is known as the "flat spot" in the ordinary carburetor. 'While driving a car this flat spot is evidenced by the fact that as the carburetor crosses over from the idle jet to the main let the engine hesitates momentarily and then takes hold.

Another dificulty arising in connection with carburetors having an air bled idle Jet below the throttle is that if the throttle is suddenly opened, the idle Jet will quit feeding and the fuel in the channel leading from the bowl to the idle jet will immediately drop to the fuellevel or even lower than the normal fuel level if the vehicle is travelling around the corner, causing the fuel in the bowl to wash to the side of the carburetor bowl opposite that where the idle channel terminates in the bowl. Then if the throttle is closed while this conditions obtains, the engine will miss; in I fact, it will die if the clutch is disengaged. Dying of the engine is caused by the fact that the'gasoline is so low in the idle channel that time is required for it to be drawn up and out of the idle Set.

One object of this invention is to eliminate this so-called cross-over or flat spot in a carburetor when changing over from the idle jet to the main jet. This object is achieved by arranging the main fuel jet so that at idle it is sub- Jected to a sufficiently high vacuum to keep the fuel up in the main jet at a higher level than the level of the fuel in the fuel bowl where it is discharging or ready to discharge immediately upon changing over from idle to part or full throttle.

Another object is to prevent the engine from dying or stalling when going around corners or suddenly openingand closing the throttle and this is accomplished by restricting the fuel channel that leads to the idle jet between air bleed and fuel bowl, to prolong the feed-back of fuel into the bowl upon sudden opening of the throttle.

The drawing shows a vertical cross section through my carburetor.

Referring more particularly to the drawing it will be seen that the carburetor comprises a housm ing I having a passageway 2 therethrough. The

air inlet is designated 3 and the fuel outlet into the engine intake manifold is designated t, The passageway 2 is controlled by a throttle valve 5 and an air valve 6 arranged to open and close in unison. Valves 5 and 6 are of the butterfly type and are fixed on shafts l and 8 which are journaled in the housing I. Shafts l and 8 have fixed thereto exteriorly of the housing I arms 9 and m, respectively. Link II is pivotally connected at its opposite ends to arms 9 and It. Shaft i also has fixed thereto an arm I2 which has a pivotal connection with rod It for manually controlling the throttle. Thus, it is seen that because of the link I l connecting arms 9 and 10, valves 5 and 6 open and close in unison,

The carburetor is provided with a conventional float bowl M and a main fuel nozzle l5 positioned in the venturi Hi, The fuel level in bowl it is indlcated at 25. The flow of fuel from the float W bowl it to and out of nozzle I5 is preferably controlled by a metering pin H. A link I8 is pivotally connected at one end to metering pin ll and at the other end to arm 9. The metering pin W is provided with the usual fiat or tapered face an it. Thus, as the throttle valve 5 opens, metering pin i7 is correspondingly raised to increase the effective size of orifice 2i! and correspondingly increase the flow of fuel out of nozzle l5.

The carburetor is provided with an idle jet 2! so positioned in the intake manifold on the engine side of throttle 5. Idle jet 2| is connected by conduit 22 with-the float bowl Hl. Bassageway 22 is provided with an air bleed 23 to atmosphere for bleeding down the manifold vacuum and utilizing the fuel. A restriction in conduit 22 that leads to idle jet is shown at 21. Idle jet 2! is also controlled by a manually adjustable valve 2%. When throttle 5 is closed, valve 2 is adjusted relative to idle jet 2! to give the proper fuel mixture for idle.

The operation of my carburetor is as follows:

1 Assuming that air valve 6 and throttle valve 5 are closed, as shown, to cause the engine to idle, there will be sufficient vacuum around main nozzle Hi to cause it to slightly feed or be just ready to feed. Adjusting screw 26 will be set to allow additional fuel for satisfactory idle. If throttle valve 5 and air valve 8 are suddenly opened, there will be no delay in the flow of fuel coming out of the main nozzle l5 and the engine will not have a flat spot or tend to stall even though the vacuum in the manifold does drop low enough to cause the idle jet 2! to cease feeding or lean out.

, If the throttle is suddenly opened and then suddenly or quickly thereafter closed, the engine will not stall, even though the clutch is disenvalve at idle position of the throttle valve closing off the passageway to create a vacuum in the intake passageway between the throttle and air gaged, because the restriction 21 prevents the fuel in channel 22 from immediately or quickly dropping to fuel level or below the normal fuel level under such operating conditions. It will be seen that portion 28 of conduit 22 under the air bleed 23 is at a point much higher than the fuel level 25. Naturally, the fuel in this conduit is as high as or higher than the fuel level in the fuel bowl when the throttle is closed again shortly after having been opened because the fuel has not enough time to flow back through restriction 27. This prevents stalling of the engine.

Air valve 6 is shown in idle position. At idle air valve 6 is closed sufficiently to produce a vacuum in the intake passageway between throttle valve 5 and air valve 6 to keep the fuel in passageway 26 up and at the outlet of nozzle l5 above the level of the fuel in bowl it so that it is ready to feed the instant the throttle and air valves are opened beyond idle position. In fact, air valve 6 can be arranged to close sufficiently at idle to keep a small amount of fuel flowing from nozzle l5 whereby upon opening the valves from idle to part or wide open throttle, an increased amount of fuel will instantaneously flow from main nozzle 5 to prevent any flat spot as fuel ceases to flow from idle jet 2| and the engine crosses over to the main power jet I5.

'In either case fuel is always present during idle at the nozzle outlet so that upon opening the valves from idle, fuel feeds immediately from nozzle l5 and no flat spot" occurs.

I claim:

1. A carburetor for an internal combustion engine comprising a housing having an intake passageway therethrough an air valve and a throttle valve in said passa eway, means positively connecting sa d air valve and throttle valve whereby the said valves open and close substantially in unison, a venturi in said passageway between the air and throttle valves, 9, fuel float bowl, a main fuel jet in said venturi, fuel metering means for controlling the flow of fuel to the main fuel jet having operative connections with the throttle valve whereby as the throttle valve opens the meterin means correspondingly admits more fuel to the main fuel jet and as the throttle valve closes the metering means correspondingly decreases the flow of fuel to the main fuel jet, a conduit connecting the main fuel jet with said fuel bowl below the fuel level, said metering means at idle position of the air valve efiecting a maximum restriction of the fuel flow from the fuel bowl to the main fuel jet, an idle jet in the said passageway on the outlet side of the throttle valve effective at idle position of the throttle valve to supply fuel into said passageway, a'second conduit connecting said idle jet with the fuel bowl below fuel level, the said air valve suflicient to keep the fuel up in the first mentioned conduit above the level of the fuel in the float bowl and at the outlet for the main fuel jet so that the fuel is ready to feed or fed slightly from said main jet whereby as the throttle valve opens from idle position fuel is immediately fed from the main jet and fuel flow from the idle jet fades out and thereby a flat spot is avoided as the fuel ceases to flow from the idle jet.

2. A carburetor for an internal combustion engine comprising a housing having an intake passageway therethrough, an air valve and a th'rottle valve in said passageway, means positively connecting said air valve and throttle valve whereby the said valves open and close substantially in unison, a venturi in said passageway between the air and throttle valves, a fuel float bowl, 2. main fuel nozzle in said venturi, a fuel conduit connecting the main fuel nozzle and the float bowl below fuel level, a fuel metering pin for controlling the flow of fuel through said conduit to themain fuel nozzle and having operative connections with the throttle valve whereby as the throttle valve opens the metering pin correspondingly admits more fuel to flow through the conduit to the main fuel nozzle and as the throttle valve closes the metering pin correspondingly decreases the flow of fuel through said conduit to the main fuel nozzle, said metering pin at idle position of the air valve effecting its maximum restriction of the said conduit leading from the fuel bowl to the main fuel nozzle so that the conduit is only slightly open and only a slight feeding of fuel from the main fuel 'nozzle into the intake passageway is possible, an idle jet in the said passageway on the outlet side of the throttle valve efiective at idle position of the throttle valve to supply fuel into said passageway, a second conduit independent of'said first conduit and connecting said idle jet with the fuel bowl below fuel level, the said air valve at idle position of the throttle valve closing off the intake passageway to create a vacuum in the intake passageway between'the throttle and air valves sufhclent to effect a slight feeding of fuel out of the main fuel nozzle whereby as the throt= tle and air valves open from idle position fuel flow out of the idle jet fades out and fuel flow from the main nozzle increases as the metering pin correspondingly decreases its restriction of the fuel conduit leading from the bowl to the main fuel nozzle. A

MARION MAILORY.

REFERENCES man The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,011,696 Winton Dec. 12, 1911 1,748,149 Simpson .Feb. 25, 1930 1,905 988 Lorenz Apr. 25, 1933 2,252,960 Brown Aug. 19, 1941 2,198,676 Mallory Apr. 30, 1940 2,270,369 Danielsen Jan. 20, 1942 

